Are decomposition and dissociation reactions the same?

I have seen these terms being used almost interchangebly, but are decomposition and dissociation reactions the same ?

• I would say they are different because I wouldn't say an acid dissociating in to its ions (in an aqueous solution) is the decomposition of the acid. However I may be proven otherwise. – LiamH Aug 10 '15 at 10:11
• Could you give us some of those examples that you mention? – pH13 - Yet another Philipp Aug 10 '15 at 12:50

A decomposition reaction is where a compound breaks up into smaller elements or compounds. For example: $$\ce{2H2O -> 2H2 + O2}$$ is an example of a decomposition reaction. Note that in this case that this is actually a reversible reaction.
A disassociation reaction is the general process where molecules split into smaller particles which can include elements, compounds, ions and radicals. For example: $$\ce{NaCl(s) -> Na+ (aq) + Cl- (aq)}$$ is a disassociation reaction.